This invention relates to the preparation of certain conjugated dienes. In a specific aspect, the invention relates to a process for preparing 2,3-dimethyl-butadiene, (E)-3-methyl-4-methylene-2-hexene and (E,E)-3,4-dimethyl-2,4-hexadiene.
Conjugated dienes are useful as monomers in the preparation of a wide variety of polymers such as elastomers and rubbers, and as chemical intermediates in the preparation of catalysts, pharmaceuticals and agrochemicals. Thus, for example, U.S. Pat. No. 4,532,301 describes the use of 2,3-dimethylbutadiene in the preparation of radial block polymer polymerization initiators.
In the preparation of such alkyl-substituted conjugated dienes, the product is often a mixture of the desired product with polymers and isomers thereof. This results in lower yields.
It is therefore an object of the invention to provide a process for preparing certain alkyl-substituted conjugated dienes in high yield and good conversion. It is another object of the invention to provide a cost effective and convenient process for preparing the alkyl-substituted conjugated dienes.